Hello dear... Asthma is caused due to broncho-constriction (obstruction of smaller airway passages) which is indicative of Hyper-responsiveness of air passages to an allergen. The symptoms as mentioned in your post are related to this. Nebulisation & Asthalin inhaler provides symptomatic relief by causing broncho-dilation (dilating the smaller airway passages, relieving the obstruction & increasing airflow to lungs) Montelukast preparations can also be used as a maintenance therapy to relieve symptoms of seasonal allergies & asthma by reducing broncho-constriction. If symptoms still persist...it will be better to consult a Pediatrician. And make sure that your son is well protected from cold, dust & other allergens. Wishing him a good health. Thanks & take care.